box2d_sys 0.2.1

Bindings for Box2D v3.0
Documentation 
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// SPDX-FileCopyrightText: 2023 Erin Catto
// SPDX-License-Identifier: MIT

#include "ctz.h"
#include "table.h"
#include "test_macros.h"

#include "box2d/base.h"

#include <stdatomic.h>

#define SET_SPAN 317
#define ITEM_COUNT ( ( SET_SPAN * SET_SPAN - SET_SPAN ) / 2 )

int TableTest( void )
{
	int power = b2BoundingPowerOf2( 3008 );
	ENSURE( power == 12 );

	int nextPowerOf2 = b2RoundUpPowerOf2( 3008 );
	ENSURE( nextPowerOf2 == ( 1 << power ) );

	const int32_t N = SET_SPAN;
	const uint32_t itemCount = ITEM_COUNT;
	bool removed[ITEM_COUNT] = { 0 };

	for ( int32_t iter = 0; iter < 1; ++iter )
	{
		b2HashSet set = b2CreateSet( 16 );

		// Fill set
		for ( int32_t i = 0; i < N; ++i )
		{
			for ( int32_t j = i + 1; j < N; ++j )
			{
				uint64_t key = B2_SHAPE_PAIR_KEY( i, j );
				b2AddKey( &set, key );
			}
		}

		ENSURE( set.count == itemCount );

		// Remove a portion of the set
		int32_t k = 0;
		uint32_t removeCount = 0;
		for ( int32_t i = 0; i < N; ++i )
		{
			for ( int32_t j = i + 1; j < N; ++j )
			{
				if ( j == i + 1 )
				{
					uint64_t key = B2_SHAPE_PAIR_KEY( i, j );
					b2RemoveKey( &set, key );
					removed[k++] = true;
					removeCount += 1;
				}
				else
				{
					removed[k++] = false;
				}
			}
		}

		ENSURE( set.count == ( itemCount - removeCount ) );

#ifndef NDEBUG
		extern _Atomic int g_probeCount;
		g_probeCount = 0;
#endif

		// Test key search
		// ~5ns per search on an AMD 7950x
		b2Timer timer = b2CreateTimer();

		k = 0;
		for ( int32_t i = 0; i < N; ++i )
		{
			for ( int32_t j = i + 1; j < N; ++j )
			{
				uint64_t key = B2_SHAPE_PAIR_KEY( j, i );
				ENSURE( b2ContainsKey( &set, key ) || removed[k] );
				k += 1;
			}
		}

		// uint64_t ticks = b2GetTicks(&timer);
		// printf("set ticks = %llu\n", ticks);

		float ms = b2GetMilliseconds( &timer );
		printf( "set: count = %d, b2ContainsKey = %.5f ms, ave = %.5f us\n", itemCount, ms, 1000.0f * ms / itemCount );

#if !NDEBUG
		float aveProbeCount = (float)g_probeCount / (float)itemCount;
		printf( "item count = %d, probe count = %d, ave probe count %.2f\n", itemCount, g_probeCount, aveProbeCount );
#endif

		// Remove all keys from set
		for ( int32_t i = 0; i < N; ++i )
		{
			for ( int32_t j = i + 1; j < N; ++j )
			{
				uint64_t key = B2_SHAPE_PAIR_KEY( i, j );
				b2RemoveKey( &set, key );
			}
		}

		ENSURE( set.count == 0 );

		b2DestroySet( &set );
	}

	return 0;
}